The present invention relates to a circuit arrangement having an electronic control device which is connected to at least one wheel speed sensor channel (6,7,8,9) transmitting wheel speed information, in particular in the form of a current signal, where the circuit arrangement (2,3,4,5) is provided with at least one monitoring module (U1,U2,U3,U4) for the at least one wheel speed sensor channel (6,7,8,9), said at least one monitoring module (U1,U2,U3,U4) being suited for monitoring an excess current fault on at least one wheel speed sensor channel; a method for monitoring and deactivating at least one wheel speed sensor where the at least one wheel speed sensor (S1,S2,S3,S4) is connected to the at least one circuit arrangement via the wheel speed sensor channel; and the utilization of the circuit arrangement and the method.
Circuit arrangements serving for processing the signals for wheel speed sensors are referenced in which the sensor currents are limited, especially in the case of excess currents. Said excess currents on sensor channels may result, among other things, from short circuits or from undesired interventions of the power supply, e.g. due to isolation defects.
Publication WO 00/22441 suggests a circuit arrangement serving for processing the signals for a wheel speed sensor provided with a circuit element for limiting the current. In case excess currents or inadmissibly high currents are detected on a wheel speed sensor channel, the current on said sensor channel is limited. Even though current limitation guarantees a certain protection of the electronic components, said components, especially integrated circuits, heat up to a relatively high degree due to fault currents. This lost heat has to be dissipated by adequate means, as e.g. cooling plates and/or fans. However, the lost heat can also stealthily damage the electronic components, particularly the integrated circuits. This possibility is in particular imminent, if e.g. an excess current fault has been detected by the motor vehicle control device, the corresponding function is no longer available and the driver has been informed by a warning lamp of the existence of a defect, but he still decides to travel a longer way or to continue a longer journey, respectively.
It is the object of the invention to describe a circuit arrangement and a method which detect excess currents in sensor channels and avoid the occurrence of such excess currents over a long period of time.